Computer navigation and fixator-assisted femoral osteotomy for correction of malunion after periprosthetic femur fracture

Management of Extra-articular Deformity in the Setting of Total Knee Arthroplasty

Extra-articular deformities of the femur and tibia in conjunction with advanced knee osteoarthritis pose unique challenges for the arthroplasty surgeon. Careful preoperative planning is needed to evaluate both the intra- and extra-articular deformities and to determine the best route to total knee arthroplasty. An intra-articular compensatory correction can typically be performed if the extra-articular deformity is distant from the joint or if preoperative templating shows that bony cuts do not interfere with ligamentous attachments. Staged osteotomy followed by arthroplasty is beneficial in severe cases in which bony cuts are excessive or would interfere with soft-tissue structures and in cases with leg-length discrepancy. Osteotomies can be performed percutaneously and fixed with intramedullary nails, external fixators, or plate and screw constructs. Ligamentous laxity after correction and risk of peroneal nerve injury are increased in extra-articular deformity cases and must be considered during the knee arthroplasty procedure with increased implant constraint and patient counseling, respectively. Computer-assisted navigation has an emerging role in total knee arthroplasty in patients with extra-articular deformity.

Total knee arthroplasty after distal femoral osteotomy long-term survivorship and clinical outcomes

Aims

There is little literature about total knee arthroplasty (TKA) after distal femoral osteotomy (DFO). Consequently, the purpose of this study was to analyze the outcomes of TKA after DFO, with particular emphasis on: survivorship free from aseptic loosening, revision, or any re-operation; complications; radiological results; and clinical outcome.

Patients and Methods

We retrospectively reviewed 29 patients (17 women, 12 men) from our total joint registry who had undergone 31 cemented TKAs after a DFO between 2000 and 2012. Their mean age at TKA was 51 years (22 to 76) and their mean body mass index 32 kg/m2 (20 to 45). The mean time between DFO and TKA was ten years (2 to 20). The mean follow-up from TKA was ten years (2 to 16). The prostheses were posterior-stabilized in 77%, varus-valgus constraint (VVC) in 13%, and cruciate-retaining in 10%. While no patient had metaphyseal fixation (e.g. cones or sleeves), 16% needed a femoral stem.

Results

The ten-year survivorship was 95% with aseptic loosening as the endpoint, 88% with revision for any reason as the endpoint, and 81% with re-operation for any reason as the endpoint. Three TKAs were revised for instability (n = 2) and aseptic tibial loosening (n = 1). No femoral component was revised for aseptic loosening. Patients under the age of 50 years were at greater risk of revision for any reason (hazard ratio 7; p = 0.03). There were two additional re-operations (6%) and four complications (13%), including three manipulations under anaesthetic (MUA; 10%). The Knee Society scores improved from a mean of 50 preoperatively (32 to 68) to a mean of 93 postoperatively (76 to 100; p < 0.001).

Conclusion

A cemented posterior-stabilized TKA has an 88% ten-year survivorship with revision for any reason as the endpoint. No femoral component was revised for aseptic loosening. Patients under the age of 50 years have a greater risk of revision. The clinical outcome was significantly improved but balancing the knee was challenging in 13% of TKAs requiring VVC. Overall, 10% of TKAs needed an MUA, and 6% of TKAs were revised for instability. Cite this article: Bone Joint J 2019;101-B:660–666.

Computer-Assisted Navigation in High Tibial Osteotomy

Computer-assisted navigation is used to improve the accuracy and precision of correction angles during high tibial osteotomy. Most studies have reported that this technique reduces the outliers of coronal alignment and unintended changes in the tibial posterior slope angle. However, more sophisticated studies are necessary to determine whether the technique will improve the clinical results and long-term survival rates. Knowledge of the navigation technology, surgical techniques and potential pitfalls, the clinical results of previous studies, and understanding of the advantages and limitations of the computer-assisted navigation are crucial to successful application of this new technique in high tibial osteotomy. Herein, we review the evidence concerning this technique from previous studies.

Applications of computer navigation in sports medicine knee surgery: an evidence-based review

Computer-assisted surgery (CAS) has been investigated in a number of sports medicine procedures in the knee. Current barriers to its widespread introduction include increased costs, duration, and invasiveness of surgery. Randomized trials on the use of CAS in anterior cruciate ligament reconstruction have failed to demonstrate a clinical benefit. Data on CAS use in high tibial osteotomy are more promising; however, long-term studies are lacking. CAS has a number of research applications in knee ligament surgery, and studies continue to explore its use in the treatment of osteochondral lesions. This article reviews the applications of CAS in sports medicine knee surgery and summarizes current literature on clinical outcomes.

TOTAL KNEE ARTHROPLASTY IN A PATIENT WITH HOFFA FRACTURE PSEUDARTHROSIS: CASE REPORT

A rare occurrence of a case of Hoffa fracture pseudarthrosis in an alcoholic patient with genu valgum associated with venous insufficiency who underwent total knee arthroplasty is reported. The literature is reviewed and the main factors for surgical indication of total knee arthroplasty after a fracture of the knee are discussed. Total knee arthroplasty was a viable option in a 60-year-old patient with Hoffa fracture pseudarthrosis and comorbidities.

Femoral corrective osteotomy for malunited supracondylar femoral fracture after TKA in a patient with rheumatoid arthritis

This article presents a case of femoral corrective osteotomy for malunited supracondylar femoral fracture after total knee arthroplasty (TKA) in a patient with rheumatoid arthritis. The patient underwent 1-stage bilateral TKA and 2-stage bilateral total hip arthroplasty 17 years prior at our institution. Her fall 10 years before led to a supracondylar femoral fracture that was treated nonoperatively for 3 months and led to malunion. Complaints of mild right knee pain and remarkable varus deformity were observed. On examination, the right knee was not swollen and tender. Range of motion (ROM) of the right knee was 0° to 130°. The patient needed crutches to ambulate. Knee score and function scores, according to the Knee Society clinical rating system, were 65 and 25 points, respectively. Radiographs after malunion showed remarkable varus knee and the femorotibial angle was 197°. At the time of surgery, the components were stable and bone union was completed. Valgus corrective osteotomy of the femur was performed using a retrograde intramedullary nail, with satisfactory results at 10-year follow-up. The patient is able to walk without a cane and has 0° to 130° ROM. Knee and function scores were 88 and 80 points, respectively. Radiographs showed complete bone union and the femorotibial angle was 179° with no loosening of the prostheses. Femoral corrective osteotomy is recommended for malunited supracondylar femoral fracture after TKA.